Automatic cut-out for electric lines.



R. JOHANSSON. AUTOMATIC CUT-OUT FOR ELECTRIC LINES. APPLICATION FILED SEPT. a0. 1916.

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Patented July 1 1917;

OFFICE.

ROBERT JOHANSSON, OF GOTTENBORG, SWEDEN.

auroma'rrc cur-our non ELECTRIC LINES. I

I Specification of Letters Patent.

Patented July 10, 1917.

Applicationfild September 80, 1916. Serial No. 123,145.

To aZZ whom it may concern:

Be it known that I, RoBnR'r' JOHANSSON, engineer, a subject of the King of Sweden,

residing at Gottenborg, in the county of Gottenborg and Bohus and Kingdom of Sweden, have invented new and useful Improvements in Automatic Cut-Outs for Electric Lines, of which the following is a specification.

This invention relates to automatic cut outs, for electric lines, which are particularly for use as a substitute for the fuse plug cut outs commonly used in house installations. Such cut outs are rather inconvenient as, after being used once, they can not be further used nor can they be repaired for a reasonable cost, and they must be thrown away andreplaced by new plugs.

I am aware that, for removing these obstacles it has been proposed to provide cut outs with electro-mechanical gears operating in a similar way to ordinary automatic switches by the aid of electro-magnets or solenoids, which interrupt the current, when the intensity has reached the predetermined maximum,- and which comprise electro-magnets adapted to operate means to release a spring actuated contact maker. Devices of this class, as hitherto known have several defects, the worst of which is, that they can be too easily switched into contactposition after the current has been broken even without removing the causes of the cut olf. This re-switching can be accomplished by simply pushing the working parts in contact by hand,bi1t such pushing can not be eflected so suddenly'and easily that the hand of the operator releases the moving part at-exactly the, same moment as the contact is reestablished, the consequence being that a 40 tEusing' of the lines, or of the apparatus therein will result. Another defect in connection with this class of cut outs is that they are liable to spark due to the unprotected' state of the contact surfaces facing one another, even in broken position.

L The object of this invention is to provide an automatic cut out, which after having been operated, can easilyfbe'resw'itche'd into working position butonly in 'suchfa my,

that it is always ready for immediate action. This is accomplished by arranging'thatthe cut out, after having interrupted the current, must be removed from its seating before it can be switched over into operative position so that, when it gets re-inserted in ts seating it is once more quite ready for- 'arms2 of said levers being elastic or spring actuated so that they tend to kee the insuaction, and consequently will immediately interrupt the current again, if the cause has not been removed. F

A further object of this invention is to provide an automatic out out in connection with the operation of which no sparks can occur and injure the operating parts or' cause a fire in the surrounding materials.

In the accompanying drawing:

Figure 1 is a longitudinal section through my improved automatic cut out with the circuit .closed and 1 Fig. 2 the same view with the operating parts of the cut out in the position they assume when the-circuit is interrupted.

A body a of porcelain or any other suitable non conducting material, and of an outward form similar to the usual fuse plug is provided with screw threads covered with sheet metal I; and a contact piece 0 for the usual holder. In the cavity 03 of the plug there is provided a plunger 6 with a knife shaped end f corresponding to a forked shoe 9 connected with the contact piece 0. The parts 7" and g constitute the two working poles of the apparatus.

A spring 7c compressed between a washer i, on the plunger 6 and a shoulder in the cavity (2 tends to' push the poles f and g apart. Normally the plunger 6 is kept in centact with the shoe 9 by the aid of a looking finger Z acting on a notch h on the plunger and provided with an extension 12. on the other side of a fulcrum m, which extension is actuated by a link 0, terminating in a hook o, suspended by one end of a lever o, mounted on a fulcrum u. The other end of the lever 'v carries an armaturer for an electro-magnet s the winding t of *which connects the sheet metal threads I) to, for instance, the fulcrum m or in any other suitable way to the lever n so that, when the plunger 6 is located with knife f in contact with shoe g, the entire current flows through the magnet s, lever 70 plunger 6, shoe 9 and contact piece 0. y

' .The' cavity d is covered by a cover a:

105 button or lmob'p.

On both sides of the shoe 9 there are proyided insulating pieces y earned by arms 3-of levers mounted on pivots 2, the other 11- lating pieces-y pushed towardt e sides of So long as the intensity of the current which passes the cut out does not exceed the maximum allowed, the parts of the apparatus will be in the position indicated by Fig.

1. Should now the intensity of the current increase, the electromagnet .9 attracts the armature 'r whereby the lever o lifts the link 0 causing the lever n to tilt, so

that the finger Z is disengaged from the notch 72. and the plunger e is pushed outwardly by the spring is, breakingthe con tact between f and g, so that no current can pass the apparatus, and the circuit is interrupted.

, As soon as the plunger e moves. as described, the insulating pieces y are brought together in front of the edge f as illustrated in Fig.2 and prevent said edge from being brought in contact with the shoe 9'. In order to prevent the plunger 6 from being forced into contact with shoe 9 in spite of the insulating pieces :1; the latter-may overlap each other as can be seen in Fig. 2 where the right handed contact piece is shown somewhat broader than the lefthanded one. 7

The only way to reestablish the contact thus broken is to push aside the insulating pieces 3 but that can-be done only by means of the projecting arms 2. These arms, however, cannot be vreached unless the whole plug a is unscrewed off the seating, whereafter the arms 2 can be spread out by hand and the contact pieces 3 thereby removed from their position in front of the plunger e.

After doing this the plunger can, by pressing on the button p, be pushed inwardly into contact with the shoe g. The plug a -is then again mounted in its seating, and the apparatus is exactly in the previous state,

so that it will once more immediately .work

and interrupt the circuit should. the current still exceed the predetermined maximum.

The insulating pieces as may be clearly understood from the awing, are positioned so as to prevent the passage of sparks between shoe- 9 and edge f and, -as said pieces are bein continually pressed by the spring actuate arms 2, toward the plun- 56 ger e, they'will slide along the surfaces thereof during the entire motionwhen breaking the current and thus are cdused to scrape 0s the sparks from the knife f, and when in the position shown in Fig. 2 there is no-opening for sparks left between the plunger 6 and shoe 9.

The metal thread 27 may be made so thin that it can serve as a common fuse, should the mechanical parts for any undue reason cease to work.

Having thus fully described and ascertained my invention and how it is tobe performed what I claim is:

'1. In an automatic cut out plug for electric lines the combination of a spring loaded contact maker forming one pole, a second pole, an electromagnetically actuated locking device for said contact maker, spring loaded insulating pieces arranged to automatically shut oif the free space between the poles when the circuit is broken,means for removing the insulating pieces so as to allow contact between the poles to bereestablished and so positioned that they, can

pieces from their shutting ofi position, only be reached, for removing the insulating when the cut out plug is removed from its seating.

3. In an automatic cut out plug for electric lines the combination of a spring loaded contact maker forming one pole, a second pole, an electromagnetically actuated locking device for said contact maker, and

insulating pieces for shutting oil the space between the contact poles when the circuit is broken, said insulating pieces overlapping one another when the circuit is broken so as to prevent the contact maker from being forced into. contact with the other pole.

In testimony whereof'I have aflixed my signature in presence of two witnesses.

c ROBERT JOHANSSON- Witnesses:

ADOLF Nonnv, IEINAR JAnsoN. 

